Door operator



Oct. 3, 1961 R. A. DEIBEL. r-:rAL 3,002,581

DOOR OPERATOR Filed May 8, 1958 2 Sheets-Sheet 1 oct. 3, 1961 Filed May8, 1958 R. A. DEIBEL ET AL DOOR OPERATOR 2 Sheets-Sheet 2 ATTORNEYSUnited States Patent Office,`

Fatented Oct. 3, i961 3,002,581 DOOR OPERATOR Raymond A. Deibel,Cheektowaga, Hobart V. Roberts, Jr., Elma, and William C. Riester,Williamsville, N.Y., assignors to Trico Products Corporation, Buffalo,N.Y.

Filed May 8, 1958, Ser. No. 733,998 7 Claims. (Cl. ISO-82) Thisinvention relates to automotive appliances and more particularly to aremotely controlled motor operated door opening and closing arrangement.

Heretofore, certain safety hazards incident to the operation of motoractuated opening and closing arrangements for vehicle doors havepr-ecluded their wide-spread acceptance, thus depriving the consumer ofa device which would have been of great convenience. More specifically,there has always been the possibility that the operator or passenger ofa vehicle would inadvertently actuate a door opening control While avehicle was in motion, wit-h the attendant possibility of injury toeither the passengers or the vehicle. Another disadvantage of many motoroperated vehicle door actuating arrangements is that they cause the doorto move at an uncontrolled speed. However it is desirable that a vehicledoor travel at a relatively slow controlled speed during the majorportion of its travel in order to avoid injury to either the door or toan obstacle in its path. Furthermore, it is imperative from a safetyviewpoint that a vehicle door travel at an increased velocity during theterminal portion of a door closing operation in order to assure properclosing, thereby preventing .the well known accidents whichmay occur dueto improper closing. In addition to the foregoing, it is many timesdesirable to convert a manual door unlatching arrangement, which isstandard equipment on most vehicles now in use, into one which iscapable of being either motor or manually actuated, as desired.lHeretofore, this procedure was costly from both material and laboraspects. It is with overcoming 'the foregoing shortcomings of the priorart that the present invention is concerned. v

lt is accordingly one of the objects of the present invention to providea simple and effective control for a remotely actuated vehicle doorwhich will prevent the door from being opened or closed when the vehicleis being driven or is capable ofV motion. In accordance with thisobject, Vthe present invention relates to an arrangement for opening andclosing a vehicle door cornprising a remotely actuated motor means forselectively opening or closing said door and interlock means coupled tosaid motor means to prevent opening of said `door when said vehicle isin motion or is capable of motion. In the specific embodiment disclosed,the interlock means is automatically actuated by the vehicle driveselector of an automatic transmission so that when the driveselector isin a drive position, the door operating motors cannot be actuatedwhether the vehicle is moving or is at a standstill. This arrangementobviates inadvertent door openings and thereby insures the safety of thepassengers and prevents injury to the vehicle.

Another object of .the present invention is to provide a remotelyactu-ated door opening and closing arrangement which not only causes thevehicle door to travel at a controlled, relatively slow speed during themajor portions of a door opening and closing operation and therebyprevents injury to the door or any object which it may encounter in itspath of travel; but also causes the door to travel 4at Yan increasedspeed during the terminal portion of a door closing operation in orderto insure proper closing thereof, thereby preventing any of the Wellknown accidents which may occur when the door is improperly closed. p gfA further object of the prjeSent invention is to provide 2 an improvedlinkage for permitting the simple conversion of a manually operatedvehicle door into one which can be actuated either by a motor from aremote control or manually in the conventional manner, as desired. Inaccordance with this object, a link made in accordance with the presentinvention replaces a conventional link which is a standard part of avehicle door, the replacing link permitting the above mentioned type ofoperation.

The various aspects of the present invention will be more fullyunderstood and other objects will become readily apparent when thefollowing portions of the speciication are read in conjunction with theaccompanying drawings wherein:

FIG. 1 is a fragmentary perspective view of an automobile containing theremotely actuated door operating arrangement of the present invention;

FIG. 2 is a view, partly in cross section, of a safety interlock switchwhich is utilized to prevent operation of the door actuating controlwhile the vehicle is capable of being driven;

FIG. 3 is a view taken along line III-III of FIG. 2;

FiG. 4 is a view, partly in cross section, of a fluid pressure switchfor actuating the door operating motor;

FIG. 5 is a VView partly in cross section of a door unlatchingarrangement which may be utilized to manually unlatch the door or forunlatching the door incidental to motor controlled door operation;

FIG. 6 is a fragmentary plan view, partly in cross section, of the motoroperated door opening arrangement of the present -invention installed inthe door of an automobile;

FIG. 7 is a detail view of a portion of the structure of FIG. 6;

FIG.' 8 is an additional detail view of a portion of the structureV ofFIG. 6;

FIG. 9 is a fragmentary plan view, partly in cross section, of amodification of the invention shown in FIG. 6; and

FIG. 10 is a detail view, in cross section, of a portion of thestructure of the modification of FIG. 9.

In FIG. 1 a portion of an automobile i0 is shown having a compressed aircontainer 11, or any other suitable source of iluid pressure, which issuitably coupled to a compressor or the like (not shown) by hose 12. Asafety interlock switch 13 (FIGS. 1, 2 and 3) is coupled to compressedair cylinder 11 by conduit 14. A bracket l5 is adapted to mountinterlock switch 13 on the steering column 16 of the automobile in sucha manner that valve stem 17 of switch 13 is adapted to be depressed whenthe automobile automatic transmission drive selector or gear shift lever18 is in a neutral position, as shown in FIG. 2. It can readily be seenthat when the drive selector 18 is in a drive position shown in FIG. 3,and in FIG. 2 dotted line showing, valve 19 will be seated against itsseat 20 and therefore prevent communication between conduit 14, which isattached to compressed air container 11, and conduit 21 which couplesinterlock switch 13 to door opening switch 2v2 (FIGS. l and 4). Thuswhen the vehicle is being driven or is capable of being driven,compressed air cannot be supplied by switch 22 to the appropriate fluidpressure door yactuating apparatus.

As can be seen from FIGS. 2 and 3, safety interlock switch 13 consistsof a body portion 23: having an upper neck portion 24 of reduceddiameter. The mounting bracket 15 is apertured to t over the neckportion 24 of the switch body. A nut 25 is adapted to be threaded ontoreduced neck portion 24'to securely fasten mounting bracket 15 to thebody of interlock switch 13. Apertures 26 and 27 are provided inmounting bracket 15 for receiving sheet metal screws (not shown), or thelike,

Y for fastening switch 13 to steering column 16. Valve stem. 17 inaddition to mounting valve 19 also mounts O-ring 28 which preventscompressed air from leaking out of the valve. Furthermore, a spring 29is provided for normally biasing valve A19 to a closed position when thedrive selector 18 is in a drive position. When starting the vehicle,shift lever 18 is lifted from its neutral position, full line showing ofFIG. 2, to the dotted position from which it is shifted laterally fordriving, This permits spring 29 to function.

The safety interlock switch 13 is opened, as shown by full lines in FIG.2, when the automobile drive selector is in a neutral position, andcompressed air may flow to door operating switch 22 (FIG. 4) throughconduit 21. When the automobile operator desires to open the automobiledoor, he merely pivots knob 30 to the left (FIG. 4), knob 3i) beingattached to flange 31 Which is, in turn, pivotally mounted, as by pin32, to upstanding fiange 33 which is affixed to the housing 34 of switch22. This movement will cause valve stem 35 to be depressed. Valve stem35 has a counter-bored portion 36 which ts loosely over hollow valvestem 37, a space 38 provided therebetween, for reasons to be explainedhereafter. As valve stem 35 moves downwardly, valve 39 will move againstthe bias of spring 40 until it engages valve seat 41. Continued movementwill cause hollow valve stern 37 to move downwardly against the bias ofspring 42 to cause valve 43 to be moved away from its seat 44. When thelatter occurs, the compressed air, which exists in conduit 2li andchamber 45, which is in communciation with conduit 21 through aperture46, will pass through apertures 43 in hollow stem 37 and into conduit 47(FIGS. l and 4) for actuating the door opening mechanism. An `O-ring 49is suitably mounted on hollow valve 37 to prevent compressed air fromleaking from the valve housing 34.

The door opening arrangement consists of an unlatching mechanism ormotor Sil (FIGS. l and 5), a double acting fluid pressure motor 51having a pistou and cylinder (FiGS. 1 and 6), and a door dampener 52,which may be integral with fluid pressure motor 51 or may be separatetherefrom.

The flow of compressed air through conduit 47, when switch 22 isactuated, causes compressed air to flow through T 53. A hose 54 has oneend thereof coupled to T 53 and the other end thereof coupled to inletconnection 54 which is mounted on housing 55 of unlatching mechanism Si)(FIG. 5). The admission of compressed air into chamber 56 of housing 55will cause relative movement between housing 55 and piston 57 againstthe bias of spring 59. Threaded into one end of housing 55 is anelongated rod 60 having a hook portion 61 at one end thereof. Threadedinto piston 57 is another elongated rod 62 having a hook portion 63 atone end thereof. A seal 64 is suitably affixed in housing 55 surroundingrod 62 to prevent leakage of compressed air from chamber 56 whilepermitting the rod to move axially. From FIG. 1 it can be seenk that thehooked end 63 of rod 62 is adapted to engage a portion 0f the manualdoor unlatching mechanism 65 which is suitably mounted within the doorof the automobile and has manual door opening handle 66 suitably coupledthereto. The rod 60 has its hooked end 61 attached to suitable mechanism67 which actuates latch 68 which, in turn, is suitably mounted in thedoor in any well known manner. Since the length of rod 62 is xed, theadmission of compressed air into chamber 56 of door unlatching mechanismwill cause housing 55 to move to the right in FIG. 5. This, in turn,will pull rod 60 to the right also and exert the necessary force onunlatching mechanism 67 to cause latch 68 to be released. It will alsobe noted that in the event it is desired to manually open the automobiledoor, handle 66 is moved in the conventional manner which will, in turn,cause the entire assembly consisting of rods 60 and 62 and housing tomove to the right in FIG. 5 .to release the latch 68 through thelatching arrangement 67.

Substantially simultaneously with the actuation of unlatching mechanism50, in the above described manner, compressed air will be admitted fromconduit 47 (FIG. 6) to one end of double acting fluid pressure motor 51which is mounted in the door of the vehicle. Motor 51 has a clevis 69which is pivotally attached by pin 70 to a rigid bracket 71 aixed to theinside of door 72. A piston 73 consisting of suitable packings 74 ismounted between washers (not numbered) which are, in turn, positioned ona portion 75 of reduced diameter of hollow shaft 76. A nut 77 securelyholds the above described piston assembly on shaft 76. The end of hollowshaft 76 which is remote from nut 77 is atiixed to link 73 by pin 79.Link 78 is, in turn, pivotally connected to door jamb 80 at point 81.The admission of compressed air from hose 47 into chamber 87 will causethe housing of fluid pressure motor 51 to move to the right in FIG. 6.Since the iluid pressure motor 51 is pivotally mounted between the doorjamb and the door by pins 81 and 70 respectively, the door will bepushed to an open position since it has already been unlatched in themanner described above.

Mounted within hollow shaft 76 is a differential dampening piston 82,which is affixed to one end of shaft S3, as by a threaded connection,the other end of shaft 83 extending through bushing 84 and nut 77 andbeing threaded into cylinder end plate 85 at 86. The rate of doormovement is controlled by this differential dampening assembly. Hollowshaft 76, which forms a dampening cylinder, is filled with a suitableincompressible hydraulic tluid which occupies the chambers to eitherside of the piston. As the door moves outwardly and upwardly in FIG. 6,the hydraulic fluid will tend to move past piston 82 from the right handchamber to the left hand chamber. Piston assembly 32 consists of pistonelements 88 and 89. As can be seen from the enlarged view in FIG. 7, asmall clearance 90 is provided between piston element 88 and the insidewall of hollow shaft 76. The inside face of piston element 88 has aspiral groove 91 therein (FIG. 8), and piston element `82 has a conduit92 therein. Since shaft 83, which mounts piston elements 89 and S8, isaflixed to cylinder end plate 85 at 86, the piston elements will move tothe right within hollow shaft 76 as the door opens. The hydraulic fluidwhich is trapped in the chamber to the right of piston element 88 istherefore forced to move through space 90, spiral groove 91, and conduit92 in order to pass to the chamber to the left of piston element 89.Depending on the size of these openings, the rate of hydraulic uid flowcan be predetermined and lthus the differential dampening arrangementwill control the speed of door opening when compressed airis admittedinto chamber 87 through hose 47.

When it is desired to close the door, knob 30 of switch 22 (FIGS. 1 and4) is pivoted to the right. This will cause the under surface 93 of knob30 to depress valve stem 94. Valve 95 which is mounted in thecounterbore 96 of valve stem 94 will therefore seat itself on valve seat97 of hollow valve stem 98 against the bias of spring 99 which tends tomaintain the valve and seat separated. Continued movement of stem 94will cause hollow valve stem y98 to move downwardly to cause valve 190to move away from its seat '101 against the bias of spring 102. Whenthis occurs compressed air will be caused to pass from hose 21 (FIGS. 1and 4) and chamber 103 into hose 104 (FIGS. l, 4 and 6) through aperture105. Thus, compressed air will be caused to pass into chamber 106 of uidpressure motor 51 (FIG. 6) and therefore cause the cylinder to move tothe left in FIG. 6 thereby causing the door to approach its closedposition.

However, it will readily be appreciated that the compressed air inchamber 87 must be vented to the atmosphere in order to permit theclosing of the door. To this end, a venting arrangement is providedwithin control valve 22 (FIG. 4). It can readily be seen that when knob30 is moved to the door closing position, the springs 42 and 40 willcause valve 43 to engage seat 44 and cause valve 39 to move away fromits seat 41, respectively. The compressed air in chamber 87 maytherefore pass back through conduit 47 (FIGS. 4 and 6) through ports 48of hollow valve stern 37, thro-ugh the hollow portion of valve stem 37in which spring 40 is located, through the space 3S between counterbore36 and the outside of valve stem 37, and then through aperture 107 tothe atmosphere. Aperture 107 may be filled with a suitable loosepacking, such as matted hair ller, `which will permit the air to passthrough aperture 37 without causing objectionable Whistling. It willalso be appreciated that valve stems 94 and 9S which control the closingof the door, in the above described manner, have similar structure forventing chamber 106 to the atmosphere to permit the compressed airtherein to discharge when the door is opened. This structure operates inthe same manner described above relative to valve stems 35 and 37, anddetailed description thereof at this point is deemed unnecessary.

As the door closes, the dampening piston consisting of elements 88 and89 mounted on shaft 83 will move to the left toward the positionrshownin FIG. 6. This will cause hydraulic uid which is trapped to the left ofthe piston element 89 to pass through the above described devious routein the piston and into the chamber to the right of piston element 88,the metering of the hydraulic iiuid through the piston assemblycontrolling the rate of door closing.

It is desirable to impart increased speed to the door at the terminalportion of the door closing operation in order to insure proper latchingthereof. This is accomplished in the present invention by rendering thedampening effect caused by piston elements 88 and 89 ineffective duringthis terminal portion of door travel. As can be seen from FIG. 7, aportion of the inside wall 103 of hollow shaft 76 is of larger diameterthan the remainder of the inside portion 109. When the door reaches apredetermined distance from its closed position, piston elements 88 and89 will enter the portion of hollow shaft 76 which has enlarged diameter108. When this occurs, the hydraulic fluid will no longer be meteredthrough the above described devious path in piston elements 88 and 89,but will be permitted to communicate directly between the chambers oneither side of the piston assembly through the space between the pistonelements and the enlarged portion 108 of the hollow shaft. This willpermit the compressed air which is supplied to chamber 106 to cause anincreased relative movement between piston 73 and the cylinder of thefluid pressure motor S1. In this manner an increased speed is impartedto door 72 prior to closing to insure that it has sufcient impetus toclose properly.

It is to be noted at this point that a snubber spring 110 is positionedwithin hollow shaft 76 (FIG. 6) between the end of piston element 89 andend plate 111. This spring serves a dual function. Firstly, on dooropening it tends to force piston assembly 88-89 to the right to overcomethe inertia thereof. Secondly, on door closing it prevents the door frommoving erratically when the dampening piston 88-89 is renderedineffective inthe above described manner. Y

A modified arrangement for practicing the present invention is disclosedin FIGS. 9 and 10. In this modication the dampening arrangement isseparate from the door opening and closing arrangement described abovein FIG. 6. The advantage of this modification is that the dampeningcylinder 76 may be installed in a remotely actuated door opening andclosing arrangement which is already in use. It can readily be seen fromFIG. 9 that a uid pressure motor 51' is provided having hoses 47' and104 coupled thereto to conduct compressed air to either end of cylinder112 for causing relative movement between piston 73 4and the cylinder toopen or close a door. One

end of shaft 113 mounts piston 73, the other end of shaft 113 beingpivoted to door jamb 114 by piu 115 and clevis 116. The end of cylinder112 which is remote from pin 1,15 is pivotally coupled, as by clevis 117and pin 119 to door strut 1.18. It can readily be seen that theadmission of compressed air through hose 47 will cause cylinder 112 tomove to the right in FIG. 9 to cause `door 120 to assume its dotted lineposition. Likewise, the admission of compressed air through hose 104will cause cylinder 112 to move to the left relative to piston 73 andtherefore cause closing of door 120 in manner similar to that describedabove relative to FIG. 6.

The dampening assembly 76 consists of a cylinder 121 (FIGS. 9 and l0)which houses a piston assembly 122 consisting of piston elements .88'and 89 which are similar in construction to pistons 88 and 89 describedabove relative to FIG. 6, and which operate in the same manner to meterhydraulic uid from chamber 123 to chamber 124 and vice versa, dependingon the direction of door movement. Shaft 125, on which piston elements88 and 89 are threaded, extends through suitably packed end plate 126 ofcylinder 121 and the end of this shaft is pivotally mounted by pin 126'to a ilange 127 which extends from door jamb 114. A clevis 128 which isconnected between the end of shaft 12S `and pin 126 forms the pivotedmounting. Another shaft 129 is threaded into piston element 89' (FIG.10) and extends through suitably packed end plate 130 mounted incylinder 121. The threading of shafts 129 and 125 into piston element 89causes piston elements S8 and 89 to be securely locked in position.Furthermore, shaft 129 provides an additional support for pistonelements 8S and 89 to cause them to move in ta desirable rectilinearpath. A clevis 128', which is mounted on the door jamb 114, pivotallysupports cylinder 5121 through pin 129.

The dampening assembly 76', as shown in FIGS. 9 and l0, is in theposition which it assumes when the door is in its fully closed position.It Will be noted that a cutaway portion 131 is provided in cylinder 121to permit free communication between the hydraulic fluid in chambers 123and 124 when piston assembly 122 is in the position shown in FIG. l0. Asthe door is opened, piston assembly 122 will move to the left relativeto cylinder 121. For the first short period of door opening the doorwill travel at a relatively high speed to insure that it is completelydisengaged from both its latching arrangement and the door jamb withwhich it is in contact in the closed position. When the piston assembly122 reaches the point at which it is no longer in the vicinity ofcutaway portion 131, a metering action will occur between the hydraulicuid in chambers 123 and 124 through the devious path such as describedabove in piston elements 88 and 89. This metering will cause the doormovement to be dampened in order to provide a controlled rate of dooropening. Likewise, when it is desired to close the door by admittingcompressed air through hose 104 into cylinder 112 (FIG. 9), thehydraulic fluid will be metered through piston assembly 122 to provide acontrolled rate of door closing. When the point is reached where pistonassembly 122 (FIG. 10)V is in the vicinity of cutaway portion 131 ofcylinder 121, a bypass will be provided around piston assembly 122 forthe hydraulic fluid passing from chamber 124 to chamber 123, and the uidpressure motor 51 will therefore impart increased speed to the door toIinsure proper closing thereof.

While certain of the appended claims refer to closing and opening of thevehicle door, it is to be understood that this terminology maycomprehend the latching and unlatching of the door also.

It can thus be seen that we have provided a unique fluid pressure doorclosing and opening arrangement for an automotive vehicle which preventsactuation of the door while the vehicle is being driven or is capable ofbeing driven, and in which the speed of door movement is controlledduring the major portions of a door opening and closing operation toprevent injury to either the vehicle or to a foreign object, and whichprovides an increased closing speed at the terminal portion of a closingoperation in order to insure proper closing of the door. Furthermore, wehave provided a linkage which permits conversion of a manually operateddoor into one which can be either motor or manually operated, asdesired.

While we have described preferred embodiments of our invention we desireit to be understood that it is not limited thereto, but may be otherwiseembodied within the scope of the following claims:

We claim:

1. A fiuid pressure door actuating arrangement comprising a cylinder, afirst piston movable in either direction relative to said cylinder,conduit connections to said cylinder for causing the portion of thecylinder to either side of said first piston to communicate with apneumatic pressure source, and a differential speed dampener in saidcylinder comprising a hollow shaft carrying said first piston, hydraulicfluid in said hollow shaft, a second piston mounted within said hollowshaft for movement relative to said hollow shaft during a door openingand closing operation, throttling means for permitting hydraulic fluidto bypass said second piston at a relatively slow rate during theinitial portion of the travel of said second piston, and means forpermitting relatively free hydraulic fluid flow in relation to saidsecond piston at the terminal portion of a door closing operationwhereby said pneumatic pressure acting on said first piston and cylindermay impart an increased speed to said door to insure proper closingthereof.

2. A fiuid pressure door actuating arrangement comprising a firstcylinder, a first piston mounted in said first cylinder, conduitconnections to said first cylinder adapted to be coupled to a pneumaticsource for causing relative movement between said first piston and saidfirst cylinder for opening or closing a door, and a differential speedhydraulic dampener associated with said first piston and first cylindercomprising a second cylinder, a second piston movable relative to saidsecond cylinder, hydraulic fiuid in said second cylinder, throttlingmeans for permitting hydraulic fiuid to bypass said second piston at apredetermined relatively slow rate during the initial portion of travelof said second piston to thereby limit the speed of door movement, andmeans associated with said dampener for permitting relatively freehydraulic fluid ow past said second piston at the terminal portion of adoor closing operation whereby said first piston and cylinder may impartan increased speed to said door to insure proper closing thereof.

3. An arrangement as set forth in claim 2 wherein said second cylindercomprises a hollow shaft which carries said first piston and whereinsaid shaft is located within said first cylinder.

4. An arrangement as set forth in claim 2 wherein said last-mentionedmeans comprises an apertured portion in said second cylinder operativeat a position where said door is proximate its closed position to permitrelatively free hydraulic fluid flow in relation to said second pistonat the terminal portion of a door closing operation whereby said firstpiston and cylinder may impart sufficient speed to said door to insureproper closing thereof.

5. An arrangement for opening and closing a vehicle door comprising asource of fiuid pressure, a door jamb, a first piston and cylinderarrangement mounted between said door and door jamb, a door latch, asecond piston and cylinder arrangement for actuating said door latch,conduits coupled between said fluid pressure source and said piston andcylinder arrangements, valve means associated with said conduits forcausing communication between said fluid pressure source and said secondpiston and cylinder for releasing said door latch and for causingcommunication between a portion of said first piston and cylinderarrangement and said fluid pressure source to open said door and forselectively causing communication between another portion of said firstpiston and cylinder arrangement and said fluid pressure source forclosing said door, dampening means associated with said first piston andcylinder arrangement for limiting the speed of door travel during theinitial portion of a door closing operation, means associated with saiddampening means for lessening the effect of said dampening means at theterminal portion of a door closing operation to permit said first pistonand cylinder means to impart sufficient momentum to said door to insureproper closing thereof, and interlock means coupled to said conduits forpreventing communication between said fluid pressure source and saidpiston and cylinder arrangements when said vehicle can be driven.

6. A combination manual-fluid pressure door latch linkage comprising adoor latch, manual means for actuating said door latch, a link couplingsaid manual means to said door latch to permit manual actuation of saiddoor latch, a fluid pressure source, a fiuid pressure motor forming apart of said link and located between said manual means and said doorlatch, and means coupling said fluid pressure motor to said fluidpressure source for permitting the actuation of said latch by fluidpressure.

7. A link for permitting either manual or remote controlled actuation ofa door latch comprising a door latch, manual means for actuating saiddoor latch, a link coupling said manual means to said door latch topermit manual actuation of said door latch, motor means forming a partof said link and located between said manual means and said door latch,an energy source, and switch means coupling said motor means to saidenergy source for selectively causing said motor means to actuate saidlatch.

References Cited in the file of this patent UNITED STATES PATENTS1,601,174 Hukill Sept. 28, 1926 1,639,747 Nelson Aug. 23, 1927 1,756,307Rowntree Apr. 29, 1930 1,909,377 Neveu May 16, 1933 1,938,502 Steindleret al. Dec. 5, 1933 2,116,446 Nishimura May 3,V 1938 2,132,767 TorenOct. ll, 1938 2,194,782 Baade Mar. 26, 1940 2,234,426 Cooley Mar. 11,1941 2,628,091 Rappl Feb. 10, 1953 2,647,536 Lunde Aug. 4, 19532,726,893 Zucker Dec. 13, 1955 2,781,781 Hruska Feb. 19, 1957 2,823,755Hall Feb. 18, 1958

